Mango Fertilizing During Fruiting

[ericalynne]

I apologize if this information is to be found elsewhere in the forum. I did do a search and did not come up with an answer.

I have six trees: Angie, Maha, Jean Ellen, Keitt, Pickering and a Carrie seedling (now grown.)

My trees are mature, but not stately mature, more like young adult mature, but flowering and fruiting well. Fruit are about 3/4 final size. Should I fertilize the trees now to keep the trees strong while putting on the final fruiting effort? Or perhaps just with K? (My soils are extremely poor, sandy, alkaline and empty of nutrients. In the color test kits, there is no color in any category.)

Thanks,
Erica

[phantomcrab]

I asked Guanabanus (Har) "What do you fertilize mangos with at this time of year?" and he replied:

0-3-16, or 0-0-16, with 4% Magnesium and a full complement of micronutrients;  also give them Gypsum (Calcium Sulfate, at at least 1/5 the volume of the mixed fertilizer applied, every time.

My soil is mulched but otherwise dry, sandy and poor. I'm not sure about the pH. I am using some Harrell's 0-0-5 with micronutrients now.

[Broman]

I though we weren't supposed to fertilize at all during fruiting...?

[phantomcrab]

I though we weren't supposed to fertilize at all during fruiting...?

Not much, but the trees do need trace elements and some potassium for the fruit. No nitrogen needed since the plants conserve it. Any extra nitrogen tends to make the trees vegetatively flush with adverse consequences for the harvest.

[Guanabanus]

The "Don't fertilize mangos during fruiting" line is correct, when talking about any of the mixed fertilizers available in most retail stores, as all those mixes contain Nitrogen. 

Nitrogen applied to mangos during fruiting season decreases fruit color, aroma, and flavor, and encourages sudden flushes of new growth.

New growth preferentially receives most of the available Calcium, and probably most of the other minerals as well, in the water coming up the xylem "veins" from the roots, as most of this water is pulled to where the most transpiration, sweating, is happening.

Calcium-starved and Boron-starved immature fruits develop "internal breakdown" and "jelly seed."

[Cookie Monster]

Very interesting. Thanks for the info.

The "Don't fertilize mangos during fruiting" line is correct, when talking about any of the mixed fertilizers available in most retail stores, as all those mixes contain Nitrogen. 

Nitrogen applied to mangos during fruiting season decreases fruit color, aroma, and flavor, and encourages sudden flushes of new growth.

New growth preferentially receives most of the available Calcium, and probably most of the other minerals as well, in the water coming up the xylem "veins" from the roots, as most of this water is pulled to where the most transpiration, sweating, is happening.

Calcium-starved and Boron-starved immature fruits develop "internal breakdown" and "jelly seed."

[Cookie Monster]

Those color test kits are unfortunately not very accurate. And, the pH test kits / tools obtained from big box stores do more harm than good. You should consider a full soil assay from a lab. Spectrum Analytic offers a full assay for $14 with a turn around time of 24 hours of receipt. See here for details: http://tropicalfruitforum.com/index.php?topic=19984.0

Assuming that you're on typical florida sand, you can lower your pH very easily with sulfur (eg,Tiger 90). Apply somewhere around 50 - 75 pounds per year for a typical 1/4 acre lot (depending on soil test results). Use caution around annonas, which in my experience can be sensitive to sulfur.

As the result of a sulfur experiment, I now have 1/4 acre of florida sand with a pH of around 3.0 :-)

I apologize if this information is to be found elsewhere in the forum. I did do a search and did not come up with an answer.

I have six trees: Angie, Maha, Jean Ellen, Keitt, Pickering and a Carrie seedling (now grown.)

My trees are mature, but not stately mature, more like young adult mature, but flowering and fruiting well. Fruit are about 3/4 final size. Should I fertilize the trees now to keep the trees strong while putting on the final fruiting effort? Or perhaps just with K? (My soils are extremely poor, sandy, alkaline and empty of nutrients. In the color test kits, there is no color in any category.)

Thanks,
Erica

[treefrog]

potassium sulfate (available at the feed store) will give you potash to support fruiting and sulfur to bring the ph down a little.  as always, light applications more often are better than large doses on a one-shot basis.

[Guanabanus]

This latter option can often work on reasonably rich soils, that already have plenty of Calcium and Magnesium.

This shouldn't be recommended for poor sandy soils.

[phantomcrab]

Label of the 0-0-5 I use - https://www.harrells.com/resources/exports/file?n=300010&t=label

[Carbo]

My Cogshall crop last year was weak,  and the few fruits that did grow were often mushy inside.  This thread has me thinking a boost of calcium and/or boron is worth considering.  Probably too late for this year's crop, but when is a good time to apply these nutrients, and what fertilizer provides them?
By the way, this year's Cogshall crop looks good, numbers wise at least.  Tree is holding about 100.

[Cookie Monster]

I've had success picking cogshall fruits green and ripening off the tree. They can be picked quite green and still be extremely delicious. If allowed to ripen on the tree, they seem to be prone to jelly seed.

My Cogshall crop last year was weak,  and the few fruits that did grow were often mushy inside.  This thread has me thinking a boost of calcium and/or boron is worth considering.  Probably too late for this year's crop, but when is a good time to apply these nutrients, and what fertilizer provides them?
By the way, this year's Cogshall crop looks good, numbers wise at least.  Tree is holding about 100.

[Cookie Monster]

Yah -- K, Mg, and Ca need to be in balance. Too much K can lower Mg and Ca availability in soils deficient in these nutrients. I've used potassium sulfate, but only because a soil test showed very high levels of both Mg and Ca.

SpectrumAnalytic has a phenomenal  library of articles on soil. A couple relevant to this topic of K balance are:

http://www.spectrumanalytic.com/support/library/ff/Is_Magnesium_a_Hidden_Problem_in_your_area.htm
http://www.spectrumanalytic.com/support/library/ff/Ca_Mg_ratio.htm
http://www.spectrumanalytic.com/support/library/ff/Mg_Basics.htm
http://www.spectrumanalytic.com/support/library/ff/Potassium_basics.htm

[Carbo]

I've had success picking cogshall fruits green and ripening off the tree. They can be picked quite green and still be extremely delicious. If allowed to ripen on the tree, they seem to be prone to jelly seed.

My Cogshall crop last year was weak,  and the few fruits that did grow were often mushy inside.  This thread has me thinking a boost of calcium and/or boron is worth considering.  Probably too late for this year's crop, but when is a good time to apply these nutrients, and what fertilizer provides them?
By the way, this year's Cogshall crop looks good, numbers wise at least.  Tree is holding about 100.

Jeff, how early is early?  Looking at my mangoes today the shoulders are pink-purple, clearly still not mature.  I'm thinking three weeks to harvest, or am I inviting jelly bellies?

[ericalynne]

Thank you Har and everyone for the input.

I have some triple phosphate to use for the 0-0-16, and a magnesium soil additive and a calcium soil additive (these are all solids) which would cover the macros.

Where do people get micronutrients? Searches on google and amazon seem to have only liquid products for hydroponics or are from India and I'd rather get something local (south Florida). Also preferably online because I do not live near any town or even stores like Home Depot, etc.

Thank you,
Erica

[treefrog]

Thank you Har and everyone for the input.

I have some triple phosphate to use for the 0-0-16, and a magnesium soil additive and a calcium soil additive (these are all solids) which would cover the macros.

Where do people get micronutrients? Searches on google and amazon seem to have only liquid products for hydroponics or are from India and I'd rather get something local (south Florida). Also preferably online because I do not live near any town or even stores like Home Depot, etc.

Thank you,
Erica

most micronutrients are easy to find.
calcium and magnesium?  dolomite lime is a mix of about 50% calcium carbonate and 40% magnesium carbonate, the rest being other minerals.  likewise seashells, though proportions may vary.
boron?  a pinch of borax
manganese?  alkaline batteries are manganese dioxide and carbon crunch up a "c" cell and you'll have more than you need.
iron?  zinc?  drop some galvanized nails in a liter of club soda, screw the top back on tight, and overnight, you have a solution of ferrous carbonate and zinc carbonate
copper?  most garden stores sell copper sulfate.
organic micronutrients?  everything that has leached out of the land for the last brazillion years is in the sea.  after a storm, go to the beach and pick up a few bushels of seaweed, bring it back, rinse it well to get rid of surface salt, and put it in your compost pile - or use it for mulch.
more sulfur and magnesium?  epsom salt is magnesium sulfate

[Cookie Monster]

It's too early now. Three weeks to harvest sounds right. To be honest, my wife is the one who determines picking time :-). I'm terrible at determining readiness to harvest. I'll let you know when she starts picking :-).

I've had success picking cogshall fruits green and ripening off the tree. They can be picked quite green and still be extremely delicious. If allowed to ripen on the tree, they seem to be prone to jelly seed.

My Cogshall crop last year was weak,  and the few fruits that did grow were often mushy inside.  This thread has me thinking a boost of calcium and/or boron is worth considering.  Probably too late for this year's crop, but when is a good time to apply these nutrients, and what fertilizer provides them?
By the way, this year's Cogshall crop looks good, numbers wise at least.  Tree is holding about 100.

Jeff, how early is early?  Looking at my mangoes today the shoulders are pink-purple, clearly still not mature.  I'm thinking three weeks to harvest, or am I inviting jelly bellies?

[Guanabanus]

Brexil and Elemax and Sequestrene and Harrells and.... are a few of the many brands that carry many micronutrient mixes.  Chelates are usually the most effective forms.

[ericalynne]

Thank you Har and everyone. I now have a mid-fruiting fertilizer program in place for my mangos.
Erica

[Carbo]

It's too early now. Three weeks to harvest sounds right. To be honest, my wife is the one who determines picking time :-). I'm terrible at determining readiness to harvest. I'll let you know when she starts picking :-).

Thanks, Jeff.